Upcoming Windows patch expected to slow Intel CPUs

[Floating Cloud]

https://www.google.co.uk/amp/s/www.theregister.co.uk/AMP/2018/01/02/intel_cpu_design_flaw/#ampshare=https://www.theregister.co.uk/2018/01/02/intel_cpu_design_flaw/

This sucks, and is going to be big news I would imagine. Newer Intel CPU have features that will reduce the performance impact, so hopefully not too severe for at least some Intel users (I am running a third gen CPU so no chance for me).

The effect depends on the process involved and CPU in the system, but the quouted performance impact seen was between 5 and 30%.

No point worrying before we get more info though, so just FYI.

 

[Printimus]

oh noes! :(

 

[Sirus7264]

Sounds like intel will be putting out a new firmware update to combat this most likely.

 

[HeadClot]

I am so happy I have my 8350 FX CPU now :D

 

[CosmicTrader]

Another reason to always go for an AMD CPU.

 

[Thalstan]

No, from what I read, the fix has to be done in software and can’t be done with a firmware update. If this is true, Intel will have a HUGE number of people upset with them...worse then the people upset with Apple over the battery issue

 

[Radegast74]

I was curious where the acronym FUCKWIT came from, so I googled a bit and found this...sigh, after that and UASS, Kernel Page Table Isolation seems so...wimpy.

from:
https://lwn.net/Articles/740608/

2) Namespace

Several people including Linus requested to change the KAISER name.

We came up with a list of technically correct acronyms:

User Address Space Separation, prefix uass_

Forcefully Unmap Complete Kernel With Interrupt Trampolines, prefix fuckwit_

but we are politically correct people so we settled for

Kernel Page Table Isolation, prefix kpti_

Linus, your call :)

 

[BUTUZ]

Another reason to always go for an AMD CPU.

So that's one reason.

 

[Michael]

What i read so far.
The fix will not affect the normal user experience. (+-2%).
Only processes which require a high virtualization like cloud computer (aws) will be heavily affected. So it might affect SC but there's nothing you can do bout it.

 

[rogesh]

What i read so far.
The fix will not affect the normal user experience. (+-2%).
Only processes which require a high virtualization like cloud computer (aws) will be heavily affected. So it might affect SC but there's nothing you can do bout it.

Aren't AMD CPUs better suited for servers? Heard such things on forums don't know if it's true tough

 

[Michael]

Aren't AMD CPUs better suited for servers? Heard such things on forums don't know if it's true tough

I'm not an Sysadmin or stuff like that just tried to follow a discussion on reddit. And that's what they said ¯\_(ツ)_/¯. So I guess if AWS uses Intel their much smarter high paid people have reasons for that.

 

[RoughGalaxy]

intel is generally better at dedicated performance. It'll do gaming great, it'll do server hosting, it'll do streaming to twitch. From what I understand AMD is moderately more efficient at doing multiple things (like playing a game AND streaming it from the same machine)

 

[mindfart]

intel is generally better at dedicated performance. It'll do gaming great, it'll do server hosting, it'll do streaming to twitch. From what I understand AMD is moderately more efficient at doing multiple things (like playing a game AND streaming it from the same machine)

I am a sysadmin.. but I have no clue about AMD in servers, because I have never seen it before. The reason they might do multitasking 'better' than intel ATM(on desktops), is because AMD is betting on lots and lots of cores.

AFAIK AMD CPU's run hotter, and use more energy than Intel CPU's, which in a datacenter is 4x cost(extra power, and extra heat coming into the DC which you have to put power in to remove)

But this upgrade will definitely hit companies like amazon, facebook, google and also smaller companies that are running everything within minimum ranges (ie. CPU utilization on 80%+). Just imagine.. you have 10k servers.. and your CPU's are being hit with a 5% performance decrease, and you want to keep the same threshold.. you will have to buy 500 machines to keep up..

 

[HeadClot]

AFAIK AMD CPU's run hotter, and use more energy than Intel CPU's, which in a datacenter is 4x cost(extra power, and extra heat coming into the DC which you have to put power in to remove)

This is true to a degree - The FX line that came before Ryzen ran hotter and used more power. Ryzen and Epyc server CPUs no longer do this due to the architecture.

 

[Floating Cloud]

So whilst this will definitely impact RSI and their hosting costs, it doesn't look like it will hit us at the game level (as per Michael's comment above). The Windows patches aren't out yet (as far as I know) but we've seen Linux kernel updates and this website has some game performance comparisons under Linux, which should reflect what we'll see with Windows too.

https://www.phoronix.com/scan.php?page=news_item&px=x86-PTI-Initial-Gaming-Tests

On a negative note, this is what RSI might be seeing with their AWS load (posted on Twitter by @timgostony 'Impact of the patch for the Intel bug on my AWS EC2 instances running Linux, a t1.micro and m3.medium. #KPTI '):

Which is either a 6% CPU usage jump, or 400% CPU usage jump, depending on how half-full/half-empty you want to be.

All good fun.